Proceedings Paper

The magnetoresistance measurements have been made on the bulk- grown GaAs-n sandwich structures and on Gunn diodes without magnetic cap. The magnetoresistance mobility has been determined by measuring the variation of the active layer resistance in a low magnetic field oriented perpendicular to the electric field direction. For this purpose the metal-semiconductor contact resistance, determined from the structure resistance vs. the magnetic field intensity and the angle between the magnetic field and the electric field, has been used. The resistivity has been obtained from the active layer resistance and the sample geometry. The concentration of charge carriers has been determined from the resistivity and the Hall mobility.